Re: Aeolid? Janolus? Stiliger? from Sulawesi

April 9, 2000
From: Kathe R. Jensen

Dear Bill and others,

Clay Carlson directed my attention to the photos of Costasiella? sp. 2 (which appeared at the time when I was still trying to get settled here in Thailand). After looking at all the pictures (you are right, that is a lot of pictures of such a small beast), I can understand the doubts of various people about the ID. However, I am mostly inclined to agreeing with the Costasiella placement. I have one undescribed species collected in Guam and also in Phuket, Thailand, in which the eyes are also behind the rhinophores. That species is very darkly pigmented, and it looks like the eyes are in little white "goggles", which must mean that they are some distance apart (namely 2 white rings). That species also has orange glands at the bases of the cerata. Unfortunately I do not have slide-scanning facility here, so I cannot attach a picture. It looks to me like your Costasiella sp. 2 has long stalks to the cerata with unbranched tubule of digestive gland, and that the dark lobules of the digestive gland (characteristic of other species of Costasiella as well) occur only in the outer part of the cerata. It certainly is an interesting little "feller", and I look forwards to hearing of anybody finding it on an identifiable alga (apparently nobody has found it on Avrainvillea, which is the most common food for this genus), and for somebody taking a look at its radula (if it is a Costasiella, the teeth should be small, narrow blade-shaped - and be of almost uniform size along the radular ribbon).
Kathe R. Jensen

jensen@ait.ac.th

Jensen, K. R., 2000 (Apr 9) Re: Aeolid? Janolus? Stiliger? from Sulawesi. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/2242

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